LONDON - A Swedish doctor says four Swedish women who have received transplanted wombs have had embryos transferred into them in an attempt to get pregnant.

Since 2012, nine women have received wombs donated by relatives in an experimental procedure designed to test whether it's possible to transfer a uterus into a woman so she can give birth to her own child. The women had in-vitro fertilization before the transplant, using their own eggs.

Dr. Mats Brannstrom at the University of Goteburg, who is leading the research, says "this is still at the testing stage but I am optimistic."

He would not say Monday whether any of the women are pregnant. Of the nine women who got transplanted wombs, two had to have them removed because of complications.